1. Field of the Invention
The present invention relates to an anti-interference device for a construction machine which moves by means of a mobile platform and performs operations by means of a plurality of rotatable operating tools, whereby it is possible completely to prevent interference between the main unit of a construction machine and a plurality of operating tools, or between the plurality of operating tools.
2. Description of the Related Art
Anti-interference devices have conventionally been provided in construction machines such that interference between the construction machine main unit, such as the mobile platform and the operating tools is prevented.
For example, Japanese Patent Publication 2-58411, which relates to a hydraulic shovel having a single back-hoe front attachment, discloses a method for restricting the range of operation, whereby a range of operation within which the crawler belts, etc. of the hydraulic shovel do not interfere with the operating tool is previously set, and when the detection results for the position of the operating tool move outside this range of operation, the operation of the operating tool is restricted.
There also exist anti-interference devices for construction machines which prevent interference between operating tools in construction machines comprising a plurality of operating tools on a single mobile platform.
For example, Japanese Patent Publication 58-19828 relates to a construction machine comprising a single rotatable back-hoe tool and an earth-moving device, wherein the lower position of the back-hoe boom cylinder and the upper position of the blade of the earth-moving device are detected by limit switches, the angle of rotation of the back-hoe is also detected, and an interference region within which the boom cylinder and earth-moving blade will interfere with other is set on the basis of these detection results, an alarm being operated when this interference region is entered. Similarly, Japanese Patent Publication 58-19827 discloses a device wherein operation in the vicinity of this interference region is automatically halted. Moreover, Japanese Patent Publication 58-45539 discloses a device wherein the velocity of approach towards this interference region is reduced.
However, since all of the conventional anti-interference devices for construction machinery described above relate to machines comprising only a single rotatable operating tool mounted on a single mobile platform, the process of predicting the interference region between operating tools or between an operating tool and the main unit of the construction machine is relatively simple, and this interference region can be set in advance, whereas in a construction machine comprising a plurality of rotatable operating tools mounted on a single mobile platform, wherein each operating tool operates freely and independently, it is difficult to set the interference region between the operating tools in advance.
In other words, since each rotatable tool on a single mobile platform is operated independently, the relative positional relationships between the operating tools change continuously in a complex manner, and consequently, it is not easy to completely prevent interference between the operating tools, and there is enormous burden on the tool operator.
Moreover, in a construction machine comprising a plurality of rotatable tools mounted on a single mobile platform, there are cases where the plurality of operating tools are used co-operatively. For example, where an object held or supported by one operating tool is transferred to another operating tool provided on the same mobile platform, and if the operating tools are simply prevented from approaching each other, co-operative operation which is a feature of such construction machines will, conversely, become impossible to implement.